In many parts of the world the electricity costs are high and/or electricity supply is unreliable, which means that in many cases conventional air cooling systems that are compressor based and electrically powered are expensive to operate and/or unreliable due to electrical power outages. For example, much of Asia spends more energy cooling buildings than it spends on lighting and heating combined.
In the North American and European markets, where rising summer temperatures result in large numbers of people switching on conventional air cooling units, the increasingly common consequence is electrical power outages due to the increasing demand on the electrical distribution system, leaving homes and businesses without cooling alternatives. Heat issues are truly global. Even in the United States, heat waves kill more people than all other natural disasters or weather encounters combined.
In addition, in many cases the electricity supply is generated by coal-fired power plants or nuclear power plants, which have associated environmental and public safety concerns.